Method of water sealing segments

ABSTRACT

A SYSTEM FOR SEALING JOINTS BETWEEN SEGMENTS ARRANGED BESIDE EACH OTHER TO LINE A CAVITY SUCH AS A TUNNEL. EACH SEGMENT HAS A GROOVED SIDE EDGE ABUTTING AN ADJOINING SEGMENT TO FORM A JOINT THEREWITH. A BITUMINOUS MATERIAL IS SITUATED WITHIN THE GROOVE AT THE JOINT AND AN ELECTRICAL CONDUCTOR IS ALSO SITUATED IN THE GROOVE, CURRENT BEING SUPPLIED TO THE CONDUCTOR FOR HEATING THE BITUMINOUS MATERIAL SO THAT IT WILL SPREAD AND FILL THE JOINT. THE SUPPLY OF ELECTRICAL CURRENT TO THE CONDUCTOR IS THEN TERMINATED SO THAT THE BITUMINOUS MATERIAL WILL HARDEN IN THE JOINT, PROVIDING AN EFFECTIVE WATER SEAL.

June 20, 1972 YOSHIRO 1'suzuKl 3,671,346

METHOD 0F WATER SEALING SEGMENTS 2. Sheets-Sheet 1 Filed Jan. 16, 1969 FIG.I

June 20, 1972 YOSHIRO TSUZUKI 3,671,346

METHOD OF WATER SEALING SEGMENTS 2 Sheets-Sheet 2 Filed Jan. 16, 1969 FIG.5

United States Patent 01 hoe 3,671,346 Patented June 20, 1972' 3,671,346 METHOD OF WATER SEALING SEGMEN TS Yoshiro Tsuzuki, 808 Seijo-cho Setagaya-ku,

Tokyo, Japan Filed Jan. 16, 1969, Ser. No. 792,236 Claims priority, application Japan, Nov. 11, 1968, 43/79,941; Dec. 10, 1968, 43/90,062 Int. Cl. F16] 13/12; Hb 3/10 US. Cl. 156-145 1 Claim ABSTRACT OF THE DISCLOSURE A system for sealing joints between segments arranged beside each other to line 'a cavity such as a tunnel. Each segment has a grooved side edge abutting an adjoining segment to form a joint therewith. A bituminous material is situated within the groove at the joint and an electrical conductor is also situated in the groove, current being supplied to the conductor for heating the bituminous ma terial so that it will spread and fill the joint. The supply of electrical current to the conductor is then terminated so that the bituminous material will harden in the joint, providing an effective water seal.

The present invention relates to RC (reinforced concrete) segments in a shield system for construction of a tunnel or to a water sealing system for cast iron or ductile segments.

Heretofore, lead caulking has been used for sealing of cast iron or ductile segments. Also for RC segments, bituminous material or mortar dry packing or expansion cement has been used. Since it has been difficult to achieve the sealing effect with the use of a secondary covering concrete and it is necessary to seal the water completely with a joint portion of the segments, and also since it has been found impossible to completely seal the water by the conventional system, such an installation technique in such conventional system has to be of high standard. Therefore, a system of filling the joint portion of the segments by means of thiocole or epoxy group synthetic resin as a caulking agent has been developed but the existence of water content in the joint surface of the segments reduced the bonding effect, and also the material itself is expensive.

An object of the present invention resides in the use of bituminous material particularly blown asphalt as the water sealing material which is well known as a waterproofing agent conventionally and inexpensive.

Another object of the present invention is to effect the complete sealing of the water wherein a conductive heat generating material such as copper wire or stainless steel plate is disposed in the bituminous material and the bituminous material is melted due to the heat generated by the conductance and the bituminous material is well packed in every corner of the joint surface of the segments to prevent the fear of water leaks.

A further object of the present invention is to facilitate easy setting of the bituminous material to the joint surface of the segments wherein the copper or stainless steel is formed in coil, cord, rod or plate form and the material is formed in cord shape by attaching the bituminous material on its external circumference and the surface of the bituminous material is hardened to such an extent that it is no longer sticky, and is made to be flexible.

Still a further object of the present invention resides in that the heat generating material is disposed on the joint surface of the segments and the electric current is applied to the conductive heat generating material and while the temperature of the joint surface is maintained at a predetermined degree, the melting of the bituminous material is maintained at a melting temperature and the bituminous material is caused to well spread in the joint surface. The bituminous material is cooled during the spreading, whereby the fear of being plugged can be eliminated.

A still further object of the present invention is to meet the requirement of finishing the water sealing of the segments as quickly as possible.

A still further object of the present invention resides in that the water sealing of the segments is completed as soon as possible, the supply of the current to the conductive heat generating material is suspended and the melting bituminous material is relatively caused to cool comparatively fast to effect the hardening of the material through cooling and thus the water sealing work is performed speedily.

A still further object of the present invention resides in that the bituminous material is melted by means of a low voltage electric heating method and even in the work performed in the submerged water, the workmen are not subjected to danger during the operation.

A still further object of the present invention resides in that the flow of the bituminous material which is melted by the supply of the current is prevented by the formation of the joint surface of the segments in meshed form.

A still further object of the present invention resides in that the installation of the bituminous material is easily performed by fitting the bituminous material formed in cord shape in portions of the joint surface of the segments.

A still further object of the present invention resides in that the assembly work of the segments is easily performed by arranging the loose meshing of the joint surface of the segments.

A still further object of the present invention resides in making the correction which is required due to a zigzag form of the tunnel or the irregular sinking by arranging the loose meshing of the joint surface of the segments and the gap caused actually by the loose meshing is sufiiciently plugged by the filling of the bituminous material.

The description of the present invention is made with reference to the drawings wherein FIG. 1 is a perspective view of the RC segment, FIGS. 2 and 3 are cross sectional views of the water sealing material which is in cord form, FIG. 4 is a cross sectional view of the joint surface of the RC segments as shown in FIG. 1, FIG. 5 is a cross sectional view of the joint portion of the ductile segments, FIG. 6 is a perspective view of another embodiment of the RC segments, FIG. 7 is a cross sectional view of the joint portion of the RC segments as shown in FIG. 6, and FIG. 8 is a view showing the condition of the assembly of the segments.

The present invention is described hereinafter wherein FIG. 1 illustrates RC segments namely segments made of reinforced concrete and joints 2 disposed in a predetermined distance on the circumference of the segments 1. Also, a concave groove 3 in which the bituminous material as the water sealing material is inserted is continuously formed, and when the assembly is made, the concave grooves 3 register to form a hollow connecting hole. As the bituminous material, blown asphalt is employed. The blown asphalt has a hardness with which it will not blow out at a room temperature and is capable of being shaped in rod or plate form.

As for the conductive heat generating material, a relatively moderate priced copper or stainless steel is used, and said material is used by shaping it into coil or rod form or elongated plate form or ribbon tapeform. A melted asphalt is coated on the external surface of the conductive heat generating material 4 and said asphalt is hardened to form a blown asphalt layer 5, and it is shaped in cord form as a whole. From both ends of said layer, the conductive heat generating material is caused to be projected. Since this Water sealing material shaped in cord form has flexibility, it is fitted in the concave grooves 3 during the covering on the circumference of the segments 1 prior to the assembly of the segments.

There are cases wherein the water sealing material 6 is fitted in respective segments 1 to be assembled or is fitted in one segment 1 only.

The projecting portion of conductive heat generating material 4 is disposed so as to appear in the corner portion of the segments 1.

When the assembly of segments 1 having a predetermined length is completed, the conductive heat generating materials 4 are respectively connected, to each other and a power source. Low voltage current is supplied to the conductive heat generating material 4, and said voltage is in the range of 20 to 40 volts and is conducted for a period of one to two minutes. For instance, in case of copper wire, 40 v. and 100 a. and in case of stainless steel, 16 v. and 200 a. As a result of this operation, the blown asphalt is heated to a temperature in the range of 180 to 200 C. and, being melted and boiled, is inflated with an expansion coeflicient of about 10%. Thus it becomes a fluid substance so as to spread into every minute gap of the joint surface. -A portion thereof oozes out of the surface of the segments. When the heating circuit is opened, the blown asphalt hardens, and an effective water sealing effect is obtained. Namely, the blown asphalt not only fills the groove 3 but also the minute gaps caused between the abutting surfaces of the segments 1 to effect a complete water sealing.

FIG. 5 shows an embodiment wherein the water sealing material is applied on the cast iron or ductile segments and the flange 7 of the joint portion covers the water sealing material 6 in the formed concave grooves 8 and the blown asphalt is melted by the flow of heating current and the water scaling is obtained. The embodiments shown in FIGS. 6, 7 and 8 indicate that two surfaces out of the circumference of the segments are formed as a continuous concave groove 9 and the other two surfaces are formed in a continuous convex portion .10. When the segments 1 are assembled, the convex portion 10 is fitted on the concave groove 9. In this case, the width of the concave groove 9 is formed widely and the convex portion 10 is loosely fitted on the concave groove 9 so as to provide a sufiicient gap. Also, the tip of the convex portion 10 is formed in concave and convex form in saw tooth shape. the condition wherein the water sealing material 6 in cord form is fitted in the concave groove 9, the assembly of the segments 1 is carried out. In this case, the meshing of the concave groove 9 and the convex portion 10 is made loose and the gap formed whereby the assembly operation is performed speedily and the adjustment of the segments 1 in order to conform to the zigzag construction of the tunnel or the irregular sinking is made possible or it is possible to assemble the segments 1 by forming an angle.

The conductive heat generating material which is buried in the water sealing material 6 is supplied with current to melt the blown asphalt which is the water sealing material 6 and is caused to boil. It spreads to fill the gap of the joint portion. According to this method, as the joint surfaces are meshed in concave and convex form, excellent water sealing is obtained and particularly if the top portion of the convex portion 10 is formed in saw tooth form, more excellent water sealing effect can be obtained.

Also, if only the conductive heat generating material 4 is inserted in the concave groove 3, and the melting blown asphalt is poured while the electric current is applied, there is no fear of cooling in the process of pouring, and accordingly, the blown asphalt can be positively poured on the joint surface.

Thus, according to the invention, the segments are arranged beside each other to line a cavity, such as a tunnel, and each segment has a grooved side edge abutting an adjoining segment to form a joint therewith. The bituminous material is interposed in the groove at the joint and the electrically conductive material is also situated in the groove at the joint so that when current is supplied thereto the bituminous material will spread so as to fill the joint and all gaps between the segments at the joint. Thereafter, the supply of current is terminated or suspended, so as to permit the bituminous material to harden. Therefore, with the invention adjoining segments will have in a groove at their abutting side edges which form the joint therebetween a hardened bituminous material filling the joint and all gaps at the joint with the electrical conductor remaining in the bituminous material.

What is claimed is:

1. Method of water sealing of segments arranged beside each other to line a cavity and each having a grooved side edge abutting an adjoining side edge of the next segment to form a joint therewith, characterized by arranging heat generating conductive material in the joint between the segments, filling bituminous material in molten condition into the joint while electric current is supplied to the conductive material, and hardening the bituminous material by terminating the supply of electric current to the conductive material.

References Cited UNITED STATES PATENTS 1,369,919 3/1921 Eliel 285-21 X 2,721,159 10/1955 Johnston 156337 X 2,992,838 7/ 1961 Wallace 2\85-21 3,061,503 10/ 1962 Gould et a1. 2852.1 3,378,672 4/1968 Blumenkranz '2 8-5--2l X 3,454,286 7/ 1969 Anderson et al. 2852'1 FOREIGN PATENTS 211,042 9/ 1960 Austria.

CARL D. QUARFORTH, Primary Examiner E. E. LEHMANN, Assistant Examiner US. Cl. X.R. l56-275; 285-21 

